You may define up to 8 analog inputs in the configuration. You must connect analog inputs to pins P00 .. P07.

The firmware reads analog values when it sends a periodic report to a host. When the periodic report is disabled you should send the “read” request for the configured endpoint.

All analog inputs have a 12-bit resolution.

The firmware configures an ADC pin with the special “3-state” mode. The unconnected pin has a high level (3.3V). But if you configure another GPIO pin after ADC on the same port (P0x) with the “pull-down” mode, the unconnected ADC pin will have about 0.2V.

Analog input, accurate (max 1.15V) – the pin uses an internal reference voltage that is more precise than a source voltage.

Analog input, (max 3.3V) – less accurate, but it can measure higher voltage.

Source voltage – reports source power voltage. It can be used to monitor a battery level. You may assign this sensor to any unused pin.

Internal temperature – reports the temperature of the CC2530 chips. You may assign this sensor to any unused pin.

Scale factor – it is the optional scale factor. It cannot be 0. The firmware multiples the measured value by this scale factor before sending a value to a coordinator.

Zigbee cluster: ZCL_CLUSTER_ID_GEN_ANALOG_INPUT_BASIC
Zigbee attributes: 
ATTRID_IOV_BASIC_PRESENT_VALUE - the sensor value (single precision float).
ATTRID_IOV_BASIC_DESCRIPTION - the value units (V - voltage, C - temperature).

Zigbee2MQTT commands

read – immediately reads the analog input value

Topic: z2m/[friedly_name]/get/[channel]
Channel: l1, l2, l3 … l8
Payload: 1
Returns the channel state: {"[channel]": float_value}